Method for Producing Isotopes, in particular Method for Producing Radioisotopes by Means of Gamma-Beam Irradiation

Abstract

A method is described for producing a radionuclide product B. A target is provided which includes an amount of a nuclide A. A gamma (γ) beam from Compton back-scattering of laser light from an electron beam irradiates the target and thereby transmutes at least a portion of the amount of the nuclide A into the product B. Providing the target includes selecting a nuclide A which is transmutable into product B by a gamma (γ) induced nuclear reaction.

1 . A method for producing a radionuclide product B comprising:
 providing a target having an amount of a nuclide A,   providing a gamma beam by Compton back-scattering of laser light from an electron beam,   irradiating the target by the gamma beam, thereby transmuting at least a portion of the amount of the nuclide A into the product B,   wherein providing the target comprises selecting a nuclide A, such that A is transmutable into product B by one of a (γ, γ′) reaction or a (γ, n) reaction, and   wherein providing said gamma beam comprises providing a gamma beam with a photon energy between 0.5 and 10 MeV in case of a (γ, γ′) reaction and between 5 and 20 MeV in case of a (γ, n) reaction.   
     
     
         2 . The method according to  claim 1 , wherein providing the gamma beam comprises providing the gamma beam with an adjustable photon energy and adjusting the photon energy in accordance with the product B and the selected nuclide A. 
     
     
         3 . The method according to  claim 1 , wherein providing the gamma beam comprises providing the electron beam by a LINAC. 
     
     
         4 . The method according to  claim 3 , wherein said LINAC is one of an energy recovery linac (ERL) or a warm linac, or a laser-driven electron beam. 
     
     
         5 . The method according to  claim 1 , wherein the target comprises the nuclide A in enriched form or in natural abundance. 
     
     
         6 . The method according to  claim 1 , wherein providing the gamma beam comprises providing the gamma beam with a flux density at the target between 10 11  and 10 20  γ/(s cm 2 ). 
     
     
         7 . The method according to  claim 1 , wherein providing the gamma beam comprises providing the gamma beam with an opening angle of less than 10 mrad. 
     
     
         8 . The method according to  claim 1 , wherein providing the gamma beam comprises providing the gamma beam with an intensity of between 10 11  and 10 17  photons per second. 
     
     
         9 . The method according to  claim 1 , wherein providing the gamma beam comprises providing the gamma beam with an energy bandwidth FWHM between 10 −2  and 10 −10 . 
     
     
         10 . The method according to  claim 1 , wherein providing the gamma beam comprises providing the gamma beam with a cross section between 1 μm 2  and 10 mm 2  at the target. 
     
     
         11 . The method according to  claim 1 , comprising selecting the nuclide A depending on the desired radionuclide product B from the following list of combinations of nuclide A, nuclear reaction, and radionuclide B:
   195 Pt(γ,γ′) 195m Pt,  226 Ra(γ,n) 225 Ra,  48 Ca(γ, n) 47 Ca,  104 Pd(γ,n) 103 Pd,  65 Cu(γ,n) 64 Cu,  166 Er(γ,n) 165 Er,  170 Er(γ,n) 169 Er,  187 Re(γ,n) 186 Re,  117 Sn(γ,γ′) 117m Sn,  87 Sr(γ,γ′) 87m Sr,  115 In(γ,γ′) 115m In,  119 Sn(γ,γ′) 119m Sn,  123 Te(γ,γ′) 123m Te,  125 Te(γ,γ′) 125m Te,  129 Xe(γ,γ′) 129m Xe,  131 Xe(γ,γ′) 131m Xe,  135 Ba(γ,γ′) 135m Ba,  176 Lu(γ,γ′) 176m Lu,  180 Hf(γ,γ′) 180m Hf,  193 Ir(γ,γ′) 193m Ir,  52 Cr(γ,n) 51 Cr,  56 Fe(γ,n) 55 Fe,  72 Ge(γ,n) 71 Ge,  76 Se(γ,n) 75 Se,  86 Sr(γ,n) 85 Sr,  98 Ru(γ,n) 97 Ru,  108 Cd(γ,n) 107 Cd,  110 Cd(γ,n) 109 Cd,  114 Sn(γ,n) 113 Sn,  122 Te(γ,n) 121 Te,  122 Te(γ,n) 121m Te,  128 Xe(γ,n) 127 Xe,  134 Ba(γ,n) 133 Ba,  134 Ba(γ,n) 133m Ba,  140 Ce(γ,n) 139 Ce,  154 Gd(γ,n) 153 Gd,  160 Dy(γ,n) 159 Dy,  170 Yb(γ,n) 169 Yb,  176 Hf(γ,n) 175 Hf,  182 W(γ,n) 181 W,  192 Pt(γ,n) 191 Pt,  194 Pt(γ,n) 193m Pt.   
     
     
         12 . The method according to  claim 1 , wherein the step of providing the γ beam further comprises stabilizing the γ beam by monitoring at least one of the γ beam energy and the γ beam energy bandwidth, and adjusting the electron beam in accordance with a result of the monitoring. 
     
     
         13 . The method according to  claim 12 , wherein the step of monitoring comprises either
 sending a second γ beam from a γ beam production station being at least partially arranged in the electron beam to a dedicated second target, thereby releasing neutrons from the dedicated second target, and measuring the released neutron energy, or   measuring a Bragg angle of a portion of the γ beam that is Bragg-diffracted by a crystal provided in the γ beam.   
     
     
         14 . The method according to  claim 1 , wherein the method further comprises at least one step of coupling an amount of radionuclide B with a molecule such as to form a bioconjugate. 
     
     
         15 . The method according to  claim 1 , wherein the method further comprises storing the irradiated target for a period of time allowing the radionuclide product B to decay into a radionuclide end-product C. 
     
     
         16 . The method according to  claim 15 , wherein A, B, C are selected from a group comprising  226 Ra,  225 Ra,  225 Ac and  48 Ca,  47 Ca,  47 Sc. 
     
     
         17 . The method according to  claim 15 , wherein the period of time is between 0.1 and 3 times the half-life T 1/2 . 
     
     
         18 . The method according to  claim 1 , wherein the method further comprises:
 providing n targets, each comprising an amount of a respective nuclide A i , wherein the nuclides A i  may be identical or different,   positioning the n targets in a row one behind the other along the direction of the gamma beam,   irradiating the targets, thereby transmuting at least a portion of the amount of each nuclide A i  into the respective radionuclide product B i , wherein   i is an integer between 1 and n, where n is between 2 and 1000.   
     
     
         19 . The method according to  claim 1 , wherein the target comprises an implantable product. 
     
     
         20 . The method according to  claim 19 , wherein the implantable product comprises one of a stent, a seed, a biodegradable implant, and micro- or nanoparticles. 
     
     
         21 . An apparatus adapted for producing a radionuclide product B according to the method of  claim 1  comprising:
 an electron accelerator for providing the electron beam, 
 a laser light source for providing the laser light, 
 means for performing Compton back-scattering of the laser light from the electron beam for generating the gamma beam, 
 means for holding or receiving the target, such that when held or received the target is at least partially positioned within the gamma beam. 
 
     
     
         22 . The apparatus of  claim 21 , wherein the electron accelerator is adapted to provide the electron beam with at least one adjustable parameter, wherein the at least one parameter comprises one of an electron beam energy and an electron beam energy bandwidth. 
     
     
         23 . The apparatus according to  claim 22 , wherein the apparatus further comprises
 a γ beam production station being at least partially arranged in the electron beam and further being adapted to generate a second γ beam,   a second target being adapted to release neutrons upon irradiation by the second γ beam, and   means for measuring the energy of neutrons released by the second target.   
     
     
         24 . The apparatus according to  claim 21 , wherein the apparatus further comprises at least one additional laser light source for providing at least one additional laser light beam,
 additional means for performing Compton back-scattering of the at least one additional laser light beam from the electron beam for generating at least one additional gamma beam, and   additional means for holding or receiving at least one additional target, such that when held or received each of the at least one additional targets is at least partially positioned within the at least one additional beam, respectively.   
     
     
         25 . The apparatus of  claim 21 , further comprising an irradiation chamber, wherein the irradiation chamber has means for holding or receiving two or more targets aligned along a direction of the γ beam. 
     
     
         26 . The apparatus according to  claim 21 , further comprising an irradiation chamber adapted to contain the one or more targets and to contain one of a vacuum, a gas or a liquid, and wherein the irradiation chamber comprises inlet and outlet means for a gas or a liquid.